PrimeGrid’sWoodall Prime Search
On 21 March 2018, 22:13:39 UTC, PrimeGrid’s Woodall Prime Search found theWoodall mega prime:
17016602*217016602-1
nWoodall numbers are of the form: Wn=n*2 -1. Woodall numbers that are prime are called
Woodall primes. For more information, please see “Woodall prime” in The Prime Glossary(http://primes.utm.edu/glossary).

The prime is 5,122,515 digits long and enters Chris Caldwell's “The Largest Known
Primes Database” (http://primes.utm.edu/primes) ranked 1st for Woodall primes and 16thoverall. This is the 4th largest prime found by PrimeGrid, the 4th Woodall prime found byPrimeGrid, and the first Woodall prime found since December, 2007.
The discovery was made by Diego Bertolotti of Italy using an Intel(R) Core(TM) i7-2600
CPU at 3.40GHz with 8GB RAM, running Microsoft Windows 10. This computer took
about 4 days 6 hours 14 minutes to complete the primality test. Diego is a member ofthe Boinc @ Italy team.
The credits for the discovery are as follows:
1.
2.
3.
4.
5.

Diego Bertolotti (Italy), discoverer
PrimeGrid, et al.
LLR, primality program developed by Jean Pennégcwsieve, sieve program developed by Geoff Reynolds
MultiSieve, sieve program developed by Mark Rodenkirch

Entry in “The Largest Known Primes Database” can be found here:
http://primes.utm.edu/primes/page.php?id=124539
Using a single PC would have taken years to find this prime. So this timely discovery
would not have been possible without the thousands of volunteers who contributed theirspare CPU cycles. A special thanks to everyone who contributed their advice and/or
computing power to the search - especially all the sievers who work behind the scenesto make a find like this possible.
PrimeGrid’s Woodall Prime Search will continue to seek even larger primes. To join thesearch please visit PrimeGrid: http://www.primegrid.com

PrimeGrid’sWoodall Prime Search
About PrimeGrid
PrimeGrid is a distributed computing project, developed by Rytis Slatkevičius andcurrently managed by Iain Bethune, James Breslin, Scott Brown, Ulrich Fries, MichaelGoetz, Roger Karpin, Rytis Slatkevičius, and Van Zimmerman.
PrimeGrid utilizes BOINC and PRPNet to search for primes with the primary goal ofbringing the excitement of prime finding to the "everyday" computer user. Simply
download the software and let your computer do the rest. Participants can choose from avariety of prime forms to search. With a little patience, you may find a large or evenrecord breaking prime.
BOINC
The Berkeley Open Infrastructure for Network Computing (BOINC) is a software
platform for distributed computing using volunteered computer resources. It allows
users to participate in multiple distributed computing projects through a single
program. Currently BOINC is being developed by a team based at the University ofCalifornia, Berkeley led by David Anderson.
This platform currently supports projects from biology to math to astronomy. For
more information, please visit BOINC: http://boinc.berkeley.edu
PRPNetPRPNet is a client/server application written by Mark Rodenkirch that is specificallydesigned to help find prime numbers of various forms. It is easily ported between
various OS/hardware combinations. PRPNet does not run each PRP test itself, butrelies on helper programs, such as LLR, PFGW, phrot, wwww, and genefer to dothe work.
For more information, please visit PrimeGrid’s PRPNet forum thread:
http://www.primegrid.com/forum_thread.php?id=1215
For more information about PrimeGrid and a complete list of available prime search
projects, please visit:http://www.primegrid.com